1. Field of the Invention
The present invention relates to a photoelectric converting device of the gate accumulation type composed of electrostatic induction transistors or punching through bipolar transistors, and more particularly to a photoelectric converting device composed of surface-gate lateral-junction electrostatic induction transistors or punching-through bipolar transistors. Such a device is adapted for use as a solid-state image sensor.
2. Related Background Art
A known solid-state image sensor consisting of an X-Y matrix arrangement of photoelectric converting devices composed of static induction transistors (SIT) in so-called vertical structure is shown in FIGS. 2A and 2B, which are respectively a schematic plan view and a schematic cross-sectional view along a line 2B--2B in FIG. 2A.
An n.sup.+ substrate 21 constitutes a drain area (region) on which an n.sup.- channel area (region) 22 is formed. In the surface layer thereof are formed an n.sup.+ source area (region) 23 and a surrounding p.sup.+ accumulating gate area (region) 24.
The p.sup.+ accumulating gate area 24 serves to accumulate the charge accumulated by photoelectric conversion. On the gate area 24, there is formed a gate capacitor 25. Under the application of a gate readout pulse .phi..sub.G, the potential of n.sup.- channel 22 is lowered according to the amount of accumulated charge, and a drain current is amplified and generated according to the I.sub.DS -V.sub.GS characteristics of SIT.
A pixel separating area 26 is composed for example of a dielectric material or diffusion of a p.sup.+ material.
FIGS. 2A and 2B correspond to a pixel of a solid-state image sensor utilizing SIT as the pixel, and the gate capacitor C.sub.G 25 and the separating area 26 can be dispensed with if the photoelectric converting device is composed of a SIT.